Synthesis and characterization of {Ni(NO)}10 and {Co(NO)2}10 complexes supported by thiolate ligands.
Nitric oxide is an important molecule in biology and modulates a variety of physiological and pathophysiological processes. Some of its regulatory functions are exerted through interactions with redox-active elements, including iron, nickel, cobalt, and sulfur. Metalloenzymes containing [ nFe- nS] ( n = 2 or 4) clusters can be activated or inactivated by reaction with NO, affording dinitrosyl iron complexes. Studies of the NO chemistry of small-molecule iron thiolate complexes have provided insight into these biological processes and suggested probable intermediates. To explore this chemistry from a different perspective, we prepared nickel and cobalt thiolate complexes and investigated their reactions with NO and related compounds. We report here the first examples of anionic complexes containing {Ni(NO)} (10) and {Co(NO) 2} (10) units, the reactivity of which suggests possible intermediates in the interconversion of iron thiolate nitrosyl compounds. Our results demonstrate new chemistry involving NO and simple complexes of nickel and cobalt supported by thiolates, which have been known for more than 30 years. The use of mass balance methodology was key to their discovery. Among the novel complexes reported are (Et 4N) 2[Ni(NO)(SPh) 3] ( 2), from (Et 4N) 2[Ni(SPh) 4] ( 1) and NO, (Et 4N) 2[Ni 2(NO) 2(mu-SPh) 2(SPh) 2] ( 3), from 1 and NO (+) or 2 and Me 3O (+), (Et 4N)[Co(NO) 2(SPh) 2] ( 5), from (Et 4N) 2[Co(SPh) 4] ( 4) and NO, and [Co 3(NO) 6(mu-SPh) 3] ( 6), from 5 and Me 3O (+). In the syntheses of 2 and 5, NO could be replaced by the convenient solid Ph 3CSNO.
Tennyson
Andrew G
AG
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Dhar
Shanta
S
Lippard
Stephen J
SJ
D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009532:Nickel / Q000737:chemistry*; D009569:Nitric Oxide / Q000031:analogs & derivatives* / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013438:Sulfhydryl Compounds / Q000737:chemistry
D008024:Ligands; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D003035:Cobalt; D009532:Nickel